1. Field of the Invention
This invention relates to a process for chemically imparting a durable, multiple-level, pile height on at least one surface of terry towelling, terry fabric or cut pile cotton fabric.
2. Description of the Prior Art
The production of multiple-level pile height material has typically been accomplished by either Jacquard weaving or by a shearing process. In either of these two known techniques, the necessary equipment is relatively complex, thereby requiring the attention of skilled technicians and a substantial investment to both construct and operate the equipment. While the art has long recognized that cellulosic fabrics may be treated with chemical agents, a process for chemically preparing a commercially acceptable material with multiple-level pile height has heretofore not been known.
Typical of the known processes for chemically treating a non-pile cellulosic fabric, particularly cotton fabric, is the so-called mercerization technique wherein a caustic agent is used to shrink and thus strengthen the cellulosic fibers. A caustic agent may also be applied to predetermined areas of an untreated or mercerized cellulosic fabric to obtain localized shrinking and thus an ornamental effect. This latter type of process is described in U.S. Pat. No. 2,531,814. An improved modification of this technique is set forth in U.S. Pat. No. 4,108,597.
It is also known in the art to treat pile fabrics with a chemical agent. For example, U.S. Pat. No. 1,804,529 describes a method of obtaining ornamental effects on fabrics, including pile fabrics, containing an organic substitution derivative (e.g., an ester) of cellulose. The ornamental effects are obtained by treating local areas of the fabric with an alkaline paste to saponify the derivative to reconstituted cellulose, carbonizing the reconstituted cellulose, and removing the carbonized cellulose. A similar technique is disclosed in U.S. Pat. No. 2,020,698.
A further example of a chemical treatment process is set forth in U.S. Pat. No. 2,110,866. The patent describes a process for preparing a pile fabric having a plurality of pile heights. The process comprises treating predetermined areas of the fabric with a paste comprising a shrinking agent (e.g., sodium hydroxide) and then heating, washing, and drying the fabric. The resulting fabric is useful in upholstery manufacture and for decorative purposes.
U.S. Pat. No. 3,849,159 relates to another process for chemically shrinking nylon pile fabric in predetermined areas to impart an embossed effect to the fabric via a process which involves the application of a thickened shrinking agent to selected areas of the piles by conventional printing techniques. The treated fabric may be heated, washed, and dried. In this regard, also see U.S. Pat. Nos. 3,901,649, 3,953,164 and 3,989,448.
Although the above-mentioned patents disclose processes for treating certain pile fabrics, such as carpeting or upholstery, with various shrinking agents, the search has continued for a process for chemically imparting commercially acceptable, durable, multiple-level, pile height to at least one surface of terry towelling, terry fabrics or cut pile cotton fabrics. The present invention was developed as a result of that search.